High Expansion Metal Seal System
A seal system for forming a fluid seal from an inner tubular member outwardly against an outer tubular member. The seal system includes a packer element that is radially expandable from a reduced diameter, unset condition to an enlarged diameter, set condition; and a radially expandable seal element surrounding the packer element and creating a fluid sealing engagement outwardly against the outer tubular member.
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1. Field of the Invention
The present invention generally relates to radial seals used in conjunction with sealing packer devices within a wellbore.
2. Description of the Related Art
Packers are known devices that are used to create fluid seals within a wellbore. One type of packer that is commonly used is an inflatable packer. An inflatable packer typically incorporates an elastomeric packer element that is expanded by inflation into sealing engagement with a surrounding casing or tubing string. The elastomeric packer element seals directly against the interior surface of the casing or tubing string.
SUMMARY OF THE INVENTIONThe present invention provides a seal system which includes a radially expandable packer element and a seal element that radially surrounds the packer element to form a fluid seal outwardly against a surrounding outer tubular member. In described embodiments, the radially expandable seal element is metallic and forms a resilient and chemically-resistant seal against a surrounding tubular. In a preferred embodiment, the seal element is formed of a ductile metal. In currently preferred embodiments, the seal element is primarily formed of a copper-based alloy, such as beryllium bronze. Alternatively, the seal element is primarily formed of stainless steel. The design of the metal seal element permits a high degree of radial expansion without causing points of strain within the seal element that could cause the seal element to fail and rupture.
In preferred embodiments, the seal element is an annular seal which is shaped to have an unexpanded form which includes a plurality of expansion segments. The expandable segments each preferably include a pair of generally axially-directed legs and an elastically deformable web portion that joins the legs together. In various embodiments, the legs and web portion are generally C-shaped or U-shaped. During radial expansion of the seal element, the web portion is elastically deformed as the legs are angled apart from each other. In some embodiments, the seal element is at least partially hollow in that it defines an interior chamber. The chamber is preferably filled with a filler material, such as a fluid or an elastomer. The filler material helps to ensure a resilient seal is formed against the surrounding tubular.
In one method of operation, a wellbore tool string which carries a seal system is disposed into the flowbore of a wellbore. The packer element is radially expanded to cause the seal element to be radially expanded and caused to seal against the outer tubular wall of the flowbore. In another described method of operation, a radially expandable seal member similar to those described previously is expanded radially and then disposed into a groove within an inner mandrel. The inner mandrel is disposed within an outer mandrel to permit the seal member to form a fluid seal between the inner and outer mandrels.
The advantages and other aspects of the invention will be readily appreciated by those of skill in the art and better understood with further reference to the accompanying drawings in which like reference characters designate like or similar elements throughout the several figures of the drawings and wherein:
The wellbore tool string 16 incorporates an exemplary radially expandable packer device 18 in accordance with the present invention. In
An annular metallic seal element 30 radially surrounds the inflatable packer element 20 and preferably is disposed within the groove 26 of the packer element 20. The seal element 30 is preferably formed of a ductile metal such as an aluminum alloy or 3/16″ stainless steel plate metal. As shown in
The seal element 30 is preferably substantially formed of a ductile metal which is both resilient and which possesses significant shape memory so that the seal element 30 may be radially deformed in an elastic manner and will then substantially return to its radially unexpanded state. Because the seal element 30 is formed of metal, it provides good resistance to chemical deterioration, which might tend to harm or destroy an elastomeric seal. In currently preferred embodiments, the seal element 30 is formed of a copper-based alloy, such as beryllium bronze. In other embodiments, the seal element 30 is formed of a deformable stainless steel, such as a 316 stainless steel band.
Because the seal element 30 is capable of radial expansion and has shape memory that permits it to substantially return to its original configuration, the seal element 30 may be stretched radially to cause it to fit over the end portions 22 or 24 and be disposed into the groove 26 of the packer element 18. The points of stresses and strains associated with the radial expansion of the seal element 30 are distributed among the various expandable segments 36, 38, 40, 42, 44, 46, 48 and 50. The inventor has found that this is advantageous, as compared to a metal seal of substantially uniform and solid cross-section which, when deformed will tend to place significant strains upon inherent points of weakness in the structure and which can result in the seal failing.
In operation, the wellbore tool string 16 is disposed into the flowbore 14 of the casing 12. The packer element 20 is inflated to move it from the unset position, depicted in
It will be understood that the invention provides seal systems which can be incorporated into a radially expandable packer device to ensure that the packer device provides a metallic seal outwardly against the surrounding casing or other tubular member. Seal systems constructed in accordance with the present invention are capable of a high degree of radial expansion and are capable of substantially returning to their original, unexpanded condition due to the shape memory property of the metal used in its construction.
It will also be understood that, in certain aspects, the invention provides seal systems that include a packer element that is radially expandable between a reduced diameter unset position and an enlarged diameter set position. In addition, the seal system of the present invention preferably includes a seal element having an annular configuration in order to provide a complete seal about the interior surface of a surrounding outer tubular member. An annular fluid seal is created by the seal elements 30, 60, 72 or 74 outwardly against the casing 12.
Those of skill in the art will understand that, although a wellbore casing 12 and an outer mandrel 110 is illustrated as an outer tubular member, these are merely examples. In fact, a liner, production tubing string, or other tubular member, may serve as the outer tubular member against which the seal element 30, 60, 72 or 74 is set.
Those of skill in the art will recognize that numerous modifications and changes may be made to the exemplary designs and embodiments described herein and that the invention is limited only by the claims that follow and any equivalents thereof.
Claims
1. A seal system for forming a fluid seal from an inner tubular member outwardly against an outer tubular member, the seal system comprising:
- a radially expandable seal element surrounding the inner tubular member and creating a fluid sealing engagement outwardly against the outer tubular member, the seal element comprising a row of interconnected expansion segments, each of the expansion segments deforming elastically as the seal element is radially expanded.
2. The seal system of claim 1 wherein each expansion segment of the expansion segments of the seal element comprise:
- a web portion that is elastically deformable;
- first and second legs that extend from the web portion; and
- wherein the expansion segment expands by angling the legs apart from one another at the web portion.
3. The seal system of claim 2 wherein the expansion segment is generally C-shaped.
4. The seal system of claim 2 wherein the expansion segment is generally U-shaped.
5. The seal system of claim 1 wherein the seal element is substantially formed of metal.
6. The seal system of claim 5 wherein the metal is a copper alloy.
7. The seal system of claim 5 wherein the metal is stainless steel.
8. The seal system of claim 1 wherein the seal system further comprises a packer element that is radially expandable from a reduced diameter, unset condition to an enlarged diameter, set condition, the seal element forming a fluid seal against the outer tubular member when the packer element is in the set condition, and wherein the packer element includes:
- a radially enlarged end portion;
- a radially reduced groove; and wherein
- the seal element resides within the groove.
9. The seal system of claim 1 wherein the seal element defines an interior chamber.
10. The seal system of claim 9 wherein the interior chamber is filled with a fluid.
11. The seal system of claim 9 wherein the interior chamber is filled with an elastomer.
12. A seal system for forming a fluid seal from an inner tubular member outwardly against an outer tubular member, the seal system comprising:
- a metallic radially expandable seal element surrounding the inner tubular member and creating a fluid sealing engagement outwardly against the outer tubular member, the seal element comprising a row of interconnected expansion segments, each of the expansion segments deforming elastically as the seal element is radially expanded.
13. The seal system of claim 12 wherein each expansion segment of the expansion segments of the seal element comprises: wherein the expansion segment expands by angling the legs apart from one another at the web portion.
- a web portion that is elastically deformable;
- first and second legs that extend from the web portion; and
14. The seal system of claim 13 wherein the expansion segment is generally C-shaped.
15. The seal system of claim 13 wherein the expansion segment is generally U-shaped.
16. The seal system of claim 12 wherein the seal element is formed of a copper alloy.
17. The seal system of claim 12 wherein the seal element is formed of stainless steel.
18. The seal system of claim 12 wherein the outer tubular member includes a groove formed therein that is generally complimentary in shape to the seal element and into which the seal element is seated during sealing.
19. The seal system of claim 12 wherein the seal system further comprises a packer element that is radially expandable from a reduced diameter, unset condition to an enlarged diameter, set condition, the seal element forming a fluid seal against the outer tubular member when the packer element is in the set condition, and wherein:
- the packer element includes: a radially enlarged end portion; a radially reduced groove; and wherein
- the seal element resides within the groove.
20. The seal system of claim 19 wherein the packer element comprises an inflatable packer element.
21. A method of forming a fluid seal within the flowbore of outer tubular member, the method comprising the steps of:
- disposing a seal system within the flowbore of the outer tubular member, the seal system having a radially expandable seal element surrounding the packer element and creating a fluid sealing engagement outwardly against the outer tubular member when the packer element is in the set condition, the seal element comprising a row of interconnected expansion segments, each of the expansion segments deforming elastically as the packer element is radially expanded; and
- radially expanding the seal element to its set condition to cause the seal element to form a fluid seal against the outer tubular member.
22. A metallic seal element that is capable of elastic expansion or compression such that the element can be expanded or contracted so as to make assembly of the seal element possible into a seal receptacle on a non-expandable substrate.
Type: Application
Filed: May 21, 2009
Publication Date: Nov 25, 2010
Patent Grant number: 8714273
Applicant: Baker Hughes Incorporated (Houston, TX)
Inventor: Gerald D. Lynde (Houston, TX)
Application Number: 12/470,479
International Classification: E21B 33/12 (20060101); E21B 23/06 (20060101); F16J 15/02 (20060101); F16J 15/00 (20060101);